Unless you live in a location where you have a greater-than-50% chance of your car getting stolen, obliviously leaving your car alarm on to bleat its whiny, incessant klaxon every few minutes is just a really, really great way of invoking the desire to inflict grievous bodily harm on your car from your neighbors.

And if you live in a gated community, then that grievous bodily harm should be directed upon you.